Hot removing an I/O module with multiple hot plug slots

ABSTRACT

In a method for ejecting a plurality of hot plug slots sharing a power controller, a processor receives a request to eject a plurality of hot plug slots, wherein the plurality of hot plug slots share a power controller and have at least two adapters present. A processor causes an OS to incrementally eject the at least two adapters, wherein ejecting an adapter comprises the OS stopping at least one driver of the adapter, and the OS generating a request to remove power from a hot plug slot. Responsive to a request by the OS to remove power from a hot plug slot, a processor generates a signal that prevents the OS from recognizing the adapter is present in the hot plug slot. Responsive to all device drivers for the at least two adapters being stopped, a processor causes power to be removed from the plurality of hot plug slots.

FIELD OF THE INVENTION

The present invention relates generally to the field of hot plugging,and more particularly to enabling and/or disabling multiple I/O slotsthat share a power source.

BACKGROUND OF THE INVENTION

Hot plugging is a term used to describe the function of replacing,adding, or removing computer system components without shutting down thesystem. Hot plugging may be used whenever it is desirable to change theconfiguration or repair a working system without interrupting itsoperation. Hot plugging may also be used for the convenience of avoidingthe delay and nuisance of shutting down and restarting complexequipment, such as a server, which aims to be continually active. Hotplugging may be used to add or remove peripherals or components, toallow a device to synchronize data with a computer, and to replacefaulty modules without interrupting equipment operation.

SUMMARY

Aspects of an embodiment of the present invention disclose a method,computer program product, and computing system for ejecting a pluralityof hot plug slots sharing a power controller. A processor receives arequest to eject a plurality of hot plug slots, wherein the plurality ofhot plug slots share a power controller and have at least two adapterspresent. A processor causes an operating system (OS) to incrementallyeject the at least two adapters present in the plurality of hot plugslots, wherein ejecting an adapter present in a hot plug slot comprisesthe OS stopping at least one driver of the adapter, and the OSgenerating a request to remove power from the hot plug slot. Responsiveto a request by the OS to remove power from a hot plug slot of theplurality of hot plug slots, a processor generates a signal thatprevents the OS from recognizing that the adapter is present in the hotplug slot. Responsive to all device drivers for each of the at least twoadapters present in the plurality of hot plug slots being stopped, aprocessor causes power to be removed from the plurality of hot plugslots.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 depicts a diagram of a computing system, in accordance with oneembodiment of the present invention.

FIG. 2 depicts a flowchart of the steps of a hot add function executingwithin the computing system of FIG. 1, for hot adding a plurality of hotplug slots on a connected input/output (I/O) module, in accordance withone embodiment of the present invention.

FIG. 3 depicts a flowchart of the steps of a hot remove functionexecuting within the computing system of FIG. 1, for hot removing aplurality of hot plug slots on a connected I/O module, in accordancewith one embodiment of the present invention.

FIG. 4 depicts a block diagram of components of the server, inaccordance with one embodiment of the present invention.

DETAILED DESCRIPTION

The present invention may be a system, a method, and/or a computerprogram product. The computer program product may include a computerreadable storage medium (or media) having computer readable programinstructions thereon for causing a processor to carry out aspects of thepresent invention.

The computer readable storage medium can be a tangible device that canretain and store instructions for use by an instruction executiondevice. The computer readable storage medium may be, for example, but isnot limited to, an electronic storage device, a magnetic storage device,an optical storage device, an electromagnetic storage device, asemiconductor storage device, or any suitable combination of theforegoing. A non-exhaustive list of more specific examples of thecomputer readable storage medium includes the following: a portablecomputer diskette, a hard disk, a random access memory (RAM), aread-only memory (ROM), an erasable programmable read-only memory (EPROMor Flash memory), a static random access memory (SRAM), a portablecompact disc read-only memory (CD-ROM), a digital versatile disk (DVD),a memory stick, a floppy disk, a mechanically encoded device such aspunch-cards or raised structures in a groove having instructionsrecorded thereon, and any suitable combination of the foregoing. Acomputer readable storage medium, as used herein, is not to be construedas being transitory signals per se, such as radio waves or other freelypropagating electromagnetic waves, electromagnetic waves propagatingthrough a waveguide or other transmission media (e.g., light pulsespassing through a fiber-optic cable), or electrical signals transmittedthrough a wire.

Computer readable program instructions described herein can bedownloaded to respective computing/processing devices from a computerreadable storage medium or to an external computer or external storagedevice via a network, for example, the Internet, a local area network, awide area network and/or a wireless network. The network may comprisecopper transmission cables, optical transmission fibers, wirelesstransmission, routers, firewalls, switches, gateway computers and/oredge servers. A network adapter card or network interface in eachcomputing/processing device receives computer readable programinstructions from the network and forwards the computer readable programinstructions for storage in a computer readable storage medium withinthe respective computing/processing device.

Computer readable program instructions for carrying out operations ofthe present invention may be assembler instructions,instruction-set-architecture (ISA) instructions, machine instructions,machine dependent instructions, microcode, firmware instructions,state-setting data, or either source code or object code written in anycombination of one or more programming languages, including an objectoriented programming language such as Java, Smalltalk, C++ or the like,and conventional procedural programming languages, such as the “C”programming language or similar programming languages. The computerreadable program instructions may execute entirely on the user'scomputer, partly on the user's computer, as a stand-alone softwarepackage, partly on the user's computer and partly on a remote computeror entirely on the remote computer or server. In the latter scenario,the remote computer may be connected to the user's computer through anytype of network, including a local area network (LAN) or a wide areanetwork (WAN), or the connection may be made to an external computer(for example, through the Internet using an Internet Service Provider).In some embodiments, electronic circuitry including, for example,programmable logic circuitry, field-programmable gate arrays (FPGA), orprogrammable logic arrays (PLA) may execute the computer readableprogram instructions by utilizing state information of the computerreadable program instructions to personalize the electronic circuitry,in order to perform aspects of the present invention.

Aspects of the present invention are described herein with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems), and computer program products according to embodiments of theinvention. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer readable program instructions.

These computer readable program instructions may be provided to aprocessor of a general purpose computer, special purpose computer, orother programmable data processing apparatus to produce a machine, suchthat the instructions, which execute via the processor of the computeror other programmable data processing apparatus, create means forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks. These computer readable program instructionsmay also be stored in a computer readable storage medium that can directa computer, a programmable data processing apparatus, and/or otherdevices to function in a particular manner, such that the computerreadable storage medium having instructions stored therein comprises anarticle of manufacture including instructions which implement aspects ofthe function/act specified in the flowchart and/or block diagram blockor blocks.

The computer readable program instructions may also be loaded onto acomputer, other programmable data processing apparatus, or other deviceto cause a series of operational steps to be performed on the computer,other programmable apparatus or other device to produce a computerimplemented process, such that the instructions which execute on thecomputer, other programmable apparatus, or other device implement thefunctions/acts specified in the flowchart and/or block diagram block orblocks.

The present invention will now be described in detail with reference tothe Figures.

FIG. 1 depicts a diagram of computing system 10, in accordance with oneembodiment of the present invention. FIG. 1 provides only anillustration of one embodiment and does not imply any limitations withregard to the environments in which different embodiments may beimplemented.

In the depicted embodiment, computing system 10 includes server 20 andinput/output (I/O) module 30. In the depicted embodiment, I/O module 30is connected to server 20. Computing system 10 may include additionalcomputing devices, servers, computers, modules, or other devices notshown.

Server 20 may be a management server, a web server, or any otherelectronic device or computing system capable of processing computerprogram instructions and receiving and sending data. In someembodiments, server 20 may be a laptop computer, tablet computer,netbook computer, personal computer (PC), a desktop computer, a personaldigital assistant (PDA), a smart phone, or any programmable electronicdevice capable of communicating with I/O module 30 and any attacheddevices, such as peripheral component interconnect express (PCIe)adapters in PCIe slots 160A-160C. An adapter may be a hardware device orsoftware component that converts transmitted data from one presentationform to another. Expansion cards typically implement some kind ofadapter. Server 20 may contain multiple slot hot plug program 110, hotadd function 120, and hot remove function 130. In the depictedembodiment, server 20 includes root complex 135. Root complex 135includes root ports 140A-140C and hot plug controllers (HPCs) 150A-150C.In some embodiments, server 20 may include a field-programmable gatearray (FPGA) (not shown), or other integrated circuits. An FPGA is anintegrated circuit designed to be configured after manufacturing. FPGAsmay be used to implement logical functions and perform digitalcomputations. In some embodiments, a FPGA may be configured to implementthe functionality of multiple slot hot plug program 110, hot addfunction 120, and/or hot remove function 130. Server 20 may includeadditional component, as depicted and described in further detail withrespect to FIG. 4.

Root complex 135 is a component of server 20 that connects the processorand memory subsystem of server 20 to the PCIe fabric. Root complex 135generates transaction requests on behalf of the processor, which isinterconnected through a local bus. Root complex 135 may include somecombination of a capabilities register, status register, and controlregister to facilitate hot plug operations. The capabilities registermay be configured to store information relating to the capabilities andoperational features that are implemented for the PCIe device and theparameters necessary to their operation. A capabilities register mayalso store additional information, such as link width and speedsupported by the hardware. A status register may include informationregarding the current settings or status of each slot, including thestatus of attention button 170, card present status, and power faultstatus. A control register may include information forsetting/controlling power, clock, reset, indicator(s) 180, and otherfunctions for each slot. Root complex 135 may support one or more PCIeports. In the depicted example, root complex 135 includes root ports140A-140C. Each of root ports 140A-140C include a hot plug controller(HPC), see HPCs 150A-150C. Root complex 135 may include any number ofroot ports and HPCs. In some embodiments, root complex 135 isimplemented as a discrete device. In other embodiments, root complex 135may be integrated with the processor or with the chipset.

HPCs 150A-150C may each be included to facilitate hot plug operationsassociated with multiple slot hot plug program 110, hot add function120, and/or hot remove function 130. HPCs 150A-150C may each beconfigured to support hot plug operations that enable PCIe devices to beplugged into a slot without requiring a reboot if a PCIe device attachesto a slot having the features necessary to enable hot plug, such as PCIeslots 160A-160C on I/O module 30. HPCs 150A-150C may each be configuredto read and write information to the registers described with regard toroot complex 135. Generally, if a hot plug event occurs, the respectiveHPC indicates the information (i.e., the hot plug event status) on theregisters and issues an interrupt to the processor. Hot plug events mayinclude indications that the attention button has been pressed, or thata power fault has been detected. The information included in theregisters can be manipulated according to the operation associated withthe interrupt. In the depicted illustration, each of PCI slots 160A-160Ccorrespond to respective root ports 140A-140C and respective HPCs150A-150C (e.g., PCIe slot 160A is connected to root complex 135 viaroot port 140A and hot plug operations are facilitated by HPC 150A).

Multiple slot hot plug program 110 operates to enable hot plugcapabilities for an I/O module, such as I/O module 30, that includes aplurality of PCIe slots, such as PCI slots 160A-160C, and a singleattention button 170. In some embodiments, multiple slot hot plugprogram 110 includes hot add function 120 and hot remove function 130.In one embodiment, multiple slot hot plug program 110 resides on server20. In some embodiments, multiple slot hot plug program 110 resideswithin root complex 135.

Hot add function 120 operates to hot add, or initiate without rebooting,PCIe slots and associated PCIe cards located on an I/O module, such asPCIe slots 160A-160C and PCIe cards on I/O module 30, in accordance withembodiments of the present invention. After receiving a singleindication, such as an indication generated by a user selectingattention button 170, hot add function 120 may cause each of PCI slots160A-160C, and associated PCIe cards within PCIe slots 160A-160C, to behot added to expand or otherwise enhance server 20. In some embodiments,the functionality of hot add function 120 may be embodied as firmware.

Hot remove function 130 operates to hot remove, or eject without a needto reboot the system, PCIe slots and associated PCIe cards located on anI/O module, such as PCIe slots 160A-160C and PCI cards on I/O module 30,in accordance with embodiments of the present invention. After receivinga single indication, such as an indication generated by a user selectingattention button 170, hot remove function 130 may cause the operatingsystem of server 20, each of HPC 150A-150C, and other necessary softwareand/or hardware components to hot remove PCIe cards located on PCIeslots 160A-160C. Once hot remove function 130 has caused all cards to beput into a reset state, hot remove function 130 may also cause the powerto be removed from each of slots 160A-160C, allowing for the potentialremoval of I/O module 30 from server 20 and computing system 10. In someembodiments, the functionality of hot remove function 130 may beembodied as firmware.

I/O module 30 may be a modular component configured to attach to server20. I/O module 30 may include one or more I/O expansion slots. In thedepicted embodiment, I/O module 30 includes PCIe slots 160A-160C. Eachof PCIe slots 160A-160C are hot plug capable. In some embodiments, I/Omodule 30 may include a greater or fewer number of PCIe slots. In someembodiments, I/O module 30 may include hot plug capable slots of adifferent input type. I/O module 30 includes attention button 170,indicator(s) 180, and manually-operated retention latch (MRL) 190.

In some embodiments, attention button 170 is a physical button locatedon I/O module 30, communicatively connected to each HPC of HPCs150A-150C. In other embodiments, attention button 170 may be a virtualbutton accessed through an interface on a computing device, such asserver 20. Generally, attention button 170 is used by a user to initiatea hot addition or hot removal of PCIe slots located on I/O module 30,such as PCIe slots 160A-160C. In embodiments of the current invention,attention button 170 is used to hot add or hot remove all PCIe slots onI/O module 30, i.e., PCIe slots 160A-160C. Indicator(s) 180 may indicatethe power and attention state of each slot, or all of the slots locatedon I/O module 30. In some embodiments, indicator(s) 180 may be physicallights located on or near I/O module 30. In other embodiments,indicator(s) 180 may be virtual indicators located on the display of acomputing device, such as server 20. In some embodiments, MRL 190 may beused to hold PCIe cards in place, or alternatively, to hold I/O module30 in place and operatively attached to server 20 within computingsystem 10. MRL 190 may include an MRL sensor which allows HPCs 150A-150Cto detect the MRL being opened or closed. An MRL sensor may be a switch,optical device, or other type of sensor that reports the position of aslot's MRL to HPCs 150A-150C.

FIG. 2 depicts a flowchart of the steps of hot add function 120, afunction of multiple slot hot plug program 110, executing within thecomputing system of FIG. 1, in accordance with an embodiment of thepresent invention. Hot add function 120 operates to coordinate the hotadd process on all of the PCIe slots located on I/O module 30 (i.e.,PCIe slots 160A-160C, as depicted in FIG. 1), in accordance with oneembodiment of the present invention.

In one embodiment, initially, a user may physically insert or otherwiseattach I/O module 30 to server 20. I/O module 30 may include one or morePCIe cards inserted into any of PCIe slots 160A-160C. I/O module 30 mayalso include attention button 170, wherein attention button 170 is wiredto act as an attention button for all PCIe slots (i.e., PCIe slots160A-160C) on I/O module 30.

In step 210, each of HPCs 150A-150C receives an indication thatattention button 170 has been selected. As previously discussed,attention button 170 may be a physical button or virtual selectionoption on a display or interface. In some embodiments, the indicationmay be generated by a combination of the manually operated retentionlatch (MRL) being closed and attention button 170 being selected.

In step 220, responsive to receiving the indication, each of HPCs150A-150C generate a hot add event for each respective PCIe slot of PCIeslots 160A-160C. The hot add event may include instructions to power onthe respective slot of PCIe slots 160A-160C, to locate devices on eachrespective slot of PCIe slots 160A-160C, as well as instructions toconfigure and load applicable drivers for devices on each respectiveslot of PCIe slots 160A-160C. In some embodiments each respective hotplug controller, such as each of HPCs 150A-150C, may perform stepsassociated with the hot add event. In some embodiments, HPCs 150A-150Ceach send respective generated hot add events to the operating system(OS) of server 20 for completion of the hot add process.

In step 230, the OS of server 20 receives the hot add event andcompletes the hot add process for all applicable devices on PCIe slots160A-160C. Completing the hot add process may include locating andconfiguring each device and associated drivers for the device(s) locatedon PCIe slots 160A-160C. In some embodiments, the OS may activateindicator(s) 180 to indicate the slot is active. For example,indicator(s) 180 may be a light or series of lights that turn on toindicate that power is being provided to the slot and any PCIe adaptersconnected to the slot are active.

FIG. 3 depicts a flowchart of the steps of a hot remove function 130, afunction of multiple slot hot plug program 110, executing within thecomputing system of FIG. 1. Hot remove function 130 operates tocoordinate the process for hot removing multiple PCI slots on an I/Omodule, such as PCI slots 160A-160C on I/O module 30, in accordance withone embodiment of the present invention.

In one embodiment initially, one or more PCIe adapters, or PCIe cards,are operatively connected to server 20. Each PCI adapter may beconnected to server 20 through one of PCIe slots 160A-160C.

In step 310, each HPC corresponding to a PCIe slot on the I/O module,such as HPCs 150A-150C receive an indication of intent to eject therespective PCIe slot. In embodiments of the present invention, theindication is generated when a user presses attention button 170. Aspreviously discussed, attention button 170 may be a physical button or avirtual selectable element on a computer display or interface.

In step 320, each applicable HPC, such as each of HPCs 150A-150C,generates an interrupt that is sent to the OS of server 20. An interruptis a signal to the processor of a computing device indicating an eventthat needs immediate attention. HPCs 150A-150C may each store a requestfor hot removal to a register accessible by the OS of server 20.

In step 330, the OS of server 20 receives notification of the interrupt.Upon receipt of the notification, the OS of server 20 may access theregister associated with each of HPCs 150A-150C to retrieve eachapplicable request for hot removal for the respective devices and PCIeslots 160A-160C (step 340). Typically, the OS of server 20 will retrieveone request for hot removal at a time, and the OS of server 20 may beunable to perform all requests simultaneously. As such, the OS of server20 may perform steps 350 and 360, as described below, incrementally foreach applicable request for hot removal for each PCIe slot of PCI slots160A-160C.

In decision 350, the OS of server 20 determines if there is at least onePCIe adapter in any of PCIe slots 160A-160C that has the power enabled.If PCIe slots 160A-160C do not have power enabled (decision 350, nobranch), the function is complete. If PCIe slots 160A-160C have powerenabled (decision 350, yes branch), the OS of server 20 will stopapplicable device drivers for the PCIe adapter located in the respectiveslot of PCIe slots 160A-160C (step 360). As may be natively programmedto the OS of server 20, the OS of server 20 may also write therespective HPC of HPCs 150A-150C to turn off power to the respective PCIslot of PCIe slots 160A-160C. However, embodiments of the presentinvention PCIe slots 160A-160C may share a power controller. If power isremoved from a PCIe adapter before respective drivers have been stopped,and before the PCIe adapter is in a reset state, the operation ofcomputing system 10, and more specifically server 20, could becompromised.

In step 370, an FPGA (not shown), located on server 20 asserts a signalpreventing the OS of server 20 from seeing, or otherwise recognizing,the respective PCIe adapter, even if power continues to be provided tothe respective slot of PCIe slots 160A-160C. In one embodiment, the FPGAmay assert the PERST# signal for the respective slot. PERST# (PCIExpress Reset, asserted low), is a signal that indicates fundamentalreset by a PCIe port. In some embodiments, the functionality provided bythe FPGA may be integrated through the use of software, firmware, orpossibly through the use of another type of device or integratedcircuit.

In decision 380, FPGA determines if all PCIe slots on the I/O module,such as PCI slots 160A-160C on I/O module 30, are empty or if applicablePCIe adapters have been reset. If FPGA determines there are additionalPCIe adapters that have not been reset (decision 380, no branch), the OSof server 20 will continue to sequentially disable drivers associatedwith each PCIe adapter in each PCIe slot (see steps 340-370). If FPGAdetermines all of PCIe slots 160A-160C are empty or associated PCIeadapters have been reset (decision 380, yes branch), FPGA will cause thepower controller for PCIe slots 160A-160C to remove power from each ofPCIe slots 160A-160C (step 390). In embodiments of the presentinvention, the OS of server 20 will indicate, using indicator(s) 180,that the power has been removed from each slot. Once power has beenremoved, a user at server 20 may be able to physically remove I/O module30.

FIG. 4 depicts a block diagram of components of server 20, in accordancewith an illustrative embodiment of the present invention. It should beappreciated that FIG. 4 provides only an illustration of oneimplementation and does not imply any limitations with regard to theenvironments in which different embodiments may be implemented. Manymodifications to the depicted environment may be made.

Server 20 includes communications fabric 402, which providescommunications between computer processor(s) 404, memory 406, persistentstorage 408, communications unit 410, and input/output (I/O)interface(s) 412. Communications fabric 402 can be implemented with anyarchitecture designed for passing data and/or control informationbetween processors (such as microprocessors, communications and networkprocessors, etc.), system memory, peripheral devices, and any otherhardware components within a system. For example, communications fabric402 can be implemented with one or more buses.

Memory 406 and persistent storage 408 are computer readable storagemedia. In this embodiment, memory 406 includes random access memory(RAM) 414 and cache memory 416. In general, memory 406 can include anysuitable volatile or non-volatile computer readable storage media.

In some embodiments, multiple slot hot plug program 110, hot addfunction 120, and hot remove function 130 are stored in persistentstorage 408 for execution by one or more of the respective computerprocessors 404 via one or more memories of memory 406. In otherembodiments, aspects of multiple slot hot plug program 110, hot addfunction 120, and/or hot remove function 130 are stored in the FPGA orother external memory accessible by the FPGA (not shown). In someembodiments, persistent storage 408 includes a magnetic hard disk drive.Alternatively, or in addition to a magnetic hard disk drive, persistentstorage 408 can include a solid state hard drive, a semiconductorstorage device, read-only memory (ROM), erasable programmable read-onlymemory (EPROM), flash memory, or any other computer readable storagemedia that is capable of storing program instructions or digitalinformation.

The media used by persistent storage 408 may also be removable. Forexample, a removable hard drive may be used for persistent storage 408.Other examples include optical and magnetic disks, thumb drives, andsmart cards that are inserted into a drive for transfer onto anothercomputer readable storage medium that is also part of persistent storage408.

Communications unit 410, in these examples, provides for communicationswith other data processing systems or devices. In these examples,communications unit 410 includes one or more network interface cards.Communications unit 410 may provide communications through the use ofeither or both physical and wireless communications links. Multiple slothot plug program 110, hot add function 120, and hot remove function 130may be downloaded to persistent storage 408 through communications unit410.

I/O interface(s) 412 allows for input and output of data with otherdevices that may be connected to server computer 102. For example, I/Ointerface 412 may provide a connection to external devices 418 such as akeyboard, keypad, a touch screen, and/or some other suitable inputdevice. External devices 418 can also include portable computer readablestorage media such as, for example, thumb drives, portable optical ormagnetic disks, and memory cards. Software and data used to practiceembodiments of the present invention, e.g., multiple slot hot plugprogram 110, hot add function 120, and hot remove function 130, can bestored on such portable computer readable storage media and can beloaded onto persistent storage 408 via I/O interface(s) 412. I/Ointerface(s) 412 also connect to a display 420.

Display 420 provides a mechanism to display data to a user and may be,for example, a computer monitor.

The programs described herein are identified based upon the applicationfor which they are implemented in a specific embodiment of theinvention. However, it should be appreciated that any particular programnomenclature herein is used merely for convenience, and thus theinvention should not be limited to use solely in any specificapplication identified and/or implied by such nomenclature.

The flowchart and block diagrams in the Figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods, and computer program products according to variousembodiments of the present invention. In this regard, each block in theflowchart or block diagrams may represent a module, segment, or portionof instructions, which comprises one or more executable instructions forimplementing the specified logical function(s). In some alternativeimplementations, the functions noted in the block may occur out of theorder noted in the Figures. For example, two blocks shown in successionmay, in fact, be executed substantially concurrently, or the blocks maysometimes be executed in the reverse order, depending upon thefunctionality involved. It will also be noted that each block of theblock diagrams and/or flowchart illustration, and combinations of blocksin the block diagrams and/or flowchart illustration, can be implementedby special purpose hardware-based systems that perform the specifiedfunctions or acts or carry out combinations of special purpose hardwareand computer instructions.

The invention claimed is:
 1. A method comprising: receiving, by one ormore processors, a request to eject a plurality of hot plug slots froman attention button included on a removable module, wherein theplurality of hot plug slots share a power controller, have at least twoadapters present, and are located on the removable module; receiving, bya plurality of hot plug controllers which control the plurality of hotplug slots, a signal from the attention button; instructing, by one ormore processors, an operating system to eject the at least two adapterspresent in the plurality of hot plug slots, wherein ejecting an adapterpresent in a hot plug slot comprises the operating system stopping atleast one driver of the adapter, and the operating system generating arequest to remove power from the hot plug slot; responsive to a requestby the operating system to remove power from a hot plug slot of theplurality of hot plug slots, generating, by one or more processors, asignal that prevents the operating system from recognizing that theadapter is present in the hot plug slot; and responsive to all devicedrivers for each of the at least two adapters present in the pluralityof hot plug slots being stopped, causing power to be removed from theplurality of hot plug slots.
 2. The method of claim 1, wherein each hotplug slot of the plurality of hot plug slots is a PCIe slot.
 3. Themethod of claim 1, wherein the signal is a PERST# signal.
 4. The methodof claim 1, further comprising: each hot plug controller sending aninterrupt to the operating system in response to receiving a signal fromthe attention button; and the operating system obtaining a hot removalrequest from a register of one of the hot plug controllers in responseto receiving the interrupt.
 5. A computer program product comprising:one or more non-transitory computer readable storage media and programinstructions stored on the one or more non-transitory computer readablestorage media, the program instructions are executable by a processor,the program instructions comprising: program instructions to receive arequest to eject a plurality of hot plug slots from an attention buttonincluded on a removable module, wherein the plurality of hot plug slotsshare a power controller, have at least two adapters present, and arelocated on a removable module; program instructions to receive, by aplurality of hot plug controllers which control the plurality of hotplug slots, a signal from the attention button; program instructions toinstruct an operating system to eject the at least two adapters presentin the plurality of hot plug slots, wherein ejecting an adapter presentin a hot plug slot comprises the operating system stopping at least onedriver of the adapter, and the operating system generating a request toremove power from the hot plug slot; program instructions to, responsiveto a request by the operating system to remove power from a hot plugslot of the plurality of hot plug slots, generate a signal that preventsthe operating system from recognizing that the adapter is present in thehot plug slot; and program instructions to, responsive to all devicedrivers for each of the at least two adapters present in the pluralityof hot plug slots being stopped, cause power to be removed from theplurality of hot plug slots.
 6. The computer program product of claim 5,wherein each hot plug slot of the plurality of hot plug slots is a PCIeslot.
 7. The computer program product of claim 5, wherein the signal isa PERST# signal.
 8. The computer program product of claim 5, furthercomprising: program instructions to instruct each hot plug controller tosend an interrupt to the operating system in response to receiving asignal from the attention button; and program instructions to instructthe operating system to obtain a hot removal request from a register ofone of the hot plug controllers in response to receiving the interrupt.9. A computer system comprising: one or more processors, one or morecomputer readable memories, one or more computer readable storage media,and program instructions stored on at least one of the one or morecomputer readable storage media for execution by at least one of the oneor more processors via at least one of the one or more computer readablememories, the program instructions comprising: program instructions toreceive a request to eject a plurality of hot plug slots from anattention button included on a removable module, wherein the pluralityof hot plug slots share a power controller, have at least two adapterspresent, and are located on a removable module; program instructions toreceive, by a plurality of hot plug controllers which control theplurality of hot plug slots, a signal from the attention button; programinstructions to instruct an operating system to eject the at least twoadapters present in the plurality of hot plug slots, wherein ejecting anadapter present in a hot plug slot comprises the operating systemstopping at least one driver of the adapter, and the operating systemgenerating a request to remove power from the hot plug slot; programinstructions to, responsive to a request by the operating system toremove power from a hot plug slot of the plurality of hot plug slots,generate a signal that prevents the operating system from recognizingthat the adapter is present in the hot plug slot; and programinstructions to, responsive to all device drivers for each of the atleast two adapters present in the plurality of hot plug slots beingstopped, cause power to be removed from the plurality of hot plug slots.10. The computer system of claim 9, wherein each hot plug slot of theplurality of hot plug slots is a PCIe slot.
 11. The computer system ofclaim 9, wherein the signal is a PERST# signal.